Antenna adapter

Abstract

An antenna adapter, for an antenna with a recessed adapter seat with a feed bore is provided as a base with a feed aperture, the base dimensioned to seat within the adapter seat, the feed aperture aligned coaxial with the feed bore. The base may be provided with interlock cavities dimensioned to receive retaining elements of the adapter seat as the base is inserted into the adapter seat, retaining the base within the adapter seat. The base may include a coupler cavity, coupling the feed aperture to two or more output ports. The coupler cavity may have sidewall slots.

We claim: 
     
       1. An antenna adapter, for an antenna with a recessed adapter seat with a feed bore, the adapter comprising:
 a base with a feed aperture, the base dimensioned to seat within the adapter seat, the feed aperture aligned coaxially with the feed bore; 
 a cross section of the feed aperture is the same as a cross-section of the feed bore; 
 the base provided with interlock cavities dimensioned to receive retaining elements of the adapter seat as the base is inserted into the adapter seat, retaining the base within the adapter seat. 
 
     
     
       2. The antenna adapter of  claim 1 , wherein the retaining elements are clips and the interlock cavities are retaining shoulders provided in a periphery of the base. 
     
     
       3. The antenna adapter of  claim 1 , further including a generally rectangular coupling cavity linking the feed aperture to two output ports; the feed aperture and the two output ports respectively provided on opposite sides of the coupling cavity. 
     
     
       4. The antenna adapter of  claim 3 , wherein the coupling cavity is provided with a length of 1.5 to 1.7 wavelengths, a width of 0.75 to 1 wavelengths and a depth between the feed aperture and the two output ports of approximately 0.2 wavelengths;
 the wavelengths being a wavelength of a mid-band operating frequency of the adapter. 
 
     
     
       5. The antenna adapter of  claim 3 , wherein each of a width sidewall and a length sidewall of the coupling cavity is provided with slots open to an exterior of the adapter. 
     
     
       6. The antenna adapter of  claim 5 , wherein the width and length sidewalls are formed by a plurality of cylindrical pins. 
     
     
       7. The antenna adapter of  claim 6 , wherein a radius of each of the plurality of cylindrical pins is 0.05 wavelengths or less, the wavelengths being a wavelength of a mid-band operating frequency of the adapter. 
     
     
       8. The antenna adapter of  claim 5 , wherein each of the slots are generally 0.15 to 0.25 wavelengths, the wavelengths being a wavelength of a mid-band operating frequency of the adapter. 
     
     
       9. The antenna adapter of  claim 3 , wherein the two output ports are generally rectangular in shape and are respectively aligned along a length dimension thereof which is generally parallel to the length of the coupling cavity. 
     
     
       10. The antenna adapter of  claim 9 , wherein the two output ports are positioned to be aligned asymmetrically with a midpoint of the length of the coupling cavity. 
     
     
       11. The antenna adapter of  claim 10 , wherein the coupling between the feed aperture and each of the two output ports is approximately 10 dB. 
     
     
       12. The antenna adapter of  claim 10 , wherein the coupling between the feed aperture and each of the two output ports is approximately 6 dB. 
     
     
       13. The antenna adapter of  claim 9 , wherein the two output ports each have an output port width that is defined along a length sidewall of the coupling cavity, the two output ports are generally aligned with each other with respect to a midpoint of the output port width thereof, whereby generally one-half of each output port width is open to the coupling cavity. 
     
     
       14. The antenna adapter of  claim 9 , further including an inwardly projecting septum provided upon at least one sidewall of the coupling cavity. 
     
     
       15. The antenna adapter of  claim 9 , wherein the two output ports are positioned to be aligned symmetrically with a midpoint of the length of the coupling cavity. 
     
     
       16. The antenna adapter of  claim 15 , wherein the coupling between the feed aperture and each of the two output ports is approximately 3 dB.